The present invention relates to a polyorganosiloxane composition. More particularly, the present invention relates to a polyorganosiloxane composition having good curing properties at room temperature and producing cured materials having good water absorption properties.
Silicone rubbers generally have a hydrophobic nature and therefor display excellent water repellency. As a method of providing a hydrophilic nature for silicone rubbers, it is known to use a polyorganosiloxane which is modified by polyoxyalkylene as a base polymer or as an additive.
However, such a method can provide a certain extent of hydrophilic nature to a silicone rubber but cannot provide it with water absorbing properties. Additionally, this method is disadvantageous in that it degenerates the mechanical properties of silicone rubbers. Furthermore, in preparing the polyoxyalkylene-modified polyorganosiloxane used in this method, a step of copolymerizing the polyoxyalkylene compound with the polyorganosiloxane is complicated and time consuming.
Many rubber compounds are also known which contain a (co)po lymer of acrylic acid or a metal salt of acrylic acid as a filter in order to provide water absorption properties to the rubber materials. Such use of a (co)polymer of acrylic acid or a metal salt of acrylic acid presents a problem in that when it is filled in an oily or hydrophobic rubber material, the surface of the filler is coated with the hydrophobic rubber material and loses the water absorption properties.